On Friday morning, President Trump's former national security adviser, Michael Flynn, arrived at a federal court in Washington, D.C. at 10:30 a.m. ET for his plea hearing in special counsel Robert Mueller's Russia investigation. In a statement about his guilty plea, Flynn acknowledged his wrongdoing and said he agreed to cooperate with the special counsel's office."

The retired general pleaded guilty on Friday for making false statements to the FBI about two conversations he had with then-Russian ambassador Sergey Kislyak in December. A criminal information released by the special counsel office that morning stated that Flynn had made "materially false, fictitious, and fraudulent statements" regarding the conversations.

Flynn was greeted by a swarm of reporters at the federal court, though no cameras were at his plea hearing. His statement, released by his legal team shortly after he pleaded guilty, read in full:

After over 33 years of military service to our country, including nearly five years in combat away from my family, and then my decision to continue to serve the United States, it has been extraordinarily painful to endure these many months of false accusations of "treason" and other outrageous acts. Such false accusations are contrary to everything I have ever done and stood for. But I recognize that the actions I acknowledged in court today were wrong, and through my faith in God, I am working to set things right. My guilty plea and agreement to cooperate with the Special Counsel's Office reflect a decision I made in the best interests of my family and of our country. I accept full responsibility for my actions.

Flynn's guilty plea and agreement to cooperate with Mueller's investigation spells massive trouble for Trump. Brian Ross at ABC News reported on Friday that Flynn promised "full cooperation to the Mueller team" and that he is prepared to testify against Trump, his family, and others in the White House. He could also reportedly testify that "as a candidate, Donald Trump directed him to make contact with the Russians."

Trump did not immediately respond to news about Flynn's agreement with Mueller, but it's likely the president is deeply upset about the development. For months, Trump has denied any collusion between his campaign and Russian officials, most recently calling for an investigation into his election opponent Hillary Clinton instead.

Trump has made his affinity for the retired general, who was an early supporter of his candidacy, quite obvious. He hired Flynn against President Obama's counsel. He defended Flynn against outside critics, and ordered his aides to do so in the media even up until hours before he resigned in February over lying about his conversation with Kislyak. Trump himself said about Flynn's talk with Russian officials: "I don't think he did anything wrong. If anything, he did something right."

In May, as Flynn was under investigation for Trump's campaign's ties to Russia, Yahoo News reported that he told friends he was still in contact with the president. "I just got a message from the president to stay strong," Flynn reportedly said.

In the hours after Flynn's guilty plea, President Trump himself remained silent about it. The White House's lawyer, Ty Cobb, did release a statement about Flynn that attempted to distance him from the president, calling him an Obama official:

Today, Michael Flynn, a former National Security Advisor at the White House for 25 days during the Trump Administration, and a former Obama administration official, entered a guilty plea to a single count of making a false statement to the FBI.The false statements involved mirror the false statements to White House officials which resulted in his resignation in February of this year. Nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn. The conclusion of this phase of the Special Counsel's work demonstrates again that the Special Counsel is moving with all deliberate speed and clears the way for a prompt and reasonable conclusion.

Flynn's guilty plea on Friday is a major development in U.S. politics, one whose repercussions could reverberate through the topmost levels of the administration. Special counsel Mueller has held his cards close to his chest in this investigation, but some have speculated that his next target might be Jared Kushner.